1. Field of the Invention
The present invention relates to a sheet feeding device and an image forming apparatus provide with the same and, in particular, to an arrangement for maintaining the performance of a sheet feeding means for feeding out sheets.
2. Related Background Art
Hitherto, in an image forming apparatus such as a printer, a copier, a facsimile device and the like, thick paper such as a postcard or an envelope, and a special sheet such as a thin plastic plate has been used in addition to a plain paper and these sheets are fed one by one by a manual feed or fed automatically and continuously by a sheet feeding device.
Such a sheet feeding device is provided with separating means for separating sheets one by one, and in such separating means, there may be used a separating claw or a separating pad. In the case of the arrangement in which sheets are separated by such separating means, an important factor for separating sheets is force for feeding out the papers by the sheet feeding means, that is, a conveying force. When this conveying force is lowered, it causes sheet feeding failure.
Incidentally, in the sheet feeding means, there may be used rubber on its surface and, as for such rubber, rubber of EPDM system and the like is used so as to secure a large frictional coefficient between the sheet and itself.
By the way, in recent years, various types of media including such as a coat paper for exclusive use of the ink jet are used and, moreover, accompanied with the spread of printers in many countries, a plain paper peculiar to each area has come to be used. For this reason, there have been strong demands for complying with various types of sheets in the field of the sheet feeding device too.
Under these circumstances, a serious problem is the adherence of coat dust of a coat paper and various paper dust to the surface of the sheet feeding means. When the paper dust adheres to the surface of the sheet feeding means in such a manner, the conveying force of the sheet feeding means is lowered to cause sheet feeding failure.
Incidentally, there may be used a cleaning sheet and the like as a countermeasure in order to remove the coat dust and the paper dust adhered to the sheet feeding means. However, when such an additional part is used, it invites an increase in cost and, since the cleaning sheet and the like is a component different from the main body, there occurs a problem that its handling becomes inconvenient.